Electrical distributing apparatus protective devices therefor

ABSTRACT

Plug-in circuit breakers are mounted on a distribution panel. In each circuit breaker, a contact lever engages a contact in a quenching chamber. A current-responsive release mechanism disengages the lever from the contact in response to shortcircuit currents. The chamber is located in one arm of a U-shaped housing and the release mechanism in the other arm. The lever extends between the arm through the narrow central portion joining the arms. Plugs adapted to receive current extend from the housing into the space between the arms. The plugs engage jacks in the distribution panel while the U-shaped housing fits around the jacks. The release mechanism includes a spring that pushes the lever against the contact while the non-contacting end of the lever is held by a catch. A release magnet or a bimetallic member, responding to the excess current displaces the catch and releases the lever.

United States Patent Knirsch et al.

[ ELECTRICAL DISTRIBUTING APPARATUS PROTECTIVE DEVICES THEREFOR [72] Inventors: Gunther Knirsch, Bretten; Herrmann Schmitt, Heidelberg, both of 2 1 Appl. No.: 181,728

[30] Foreign Application Priority Data Sept. 26, 1970 Germany ..P 20 47 521.2

[52] US. Cl. ..335/201, 200/168, 317/122 [51] Int. Cl. ..IIOlh 9/30 [58] Field of Search.....335/20l, 202; 200/168 R, 144

R; 3l7/ll2, 118, 119,122

[56] References Cited UNITED STATES PATENTS 2,908,782 10/1959 Kiesel et al. ..335/201 3,394,329 7/1968 Heft ..335/201 3,398,249

8/ l 968 Dessert ..200/168 C 1 Sept. 12, 1972 3,422,235 l/l969 Camp ..200/144 R 3,328,553 6/1967 Gryctko ..200/168 R 3,088,055 4/1963 Schwing ..317/122 3,492,539 l/l970 Gryctko et a] ..317/119 3,522,564 8/1970 Mori et a1. ..3 35/202 Primary Examiner-Harold Broome Attorney--Toren and McGeady [5 7] ABSTRACT Plug-in circuit breakers are mounted on a distribution panel. In each circuit breaker, a contact lever engages a contact in a quenching chamber. A current-responsive release mechanism disengages the lever from the contact in response to short-circuit currents. The chamber is located in one arm of a U-shaped housing and the release mechanism in the other arm. The lever extends between the arm through the narrow central portion joining the arms. Plugs adapted to receive current extend from the housing into the space between the arms. The plugs engage jacks in the distribution panel while ,the U-shaped housing fits around the jacks. The release mechanism includes a spring that pushes the lever against the contact while the noncontacting end of the lever is held by a catch. A release magnet or a bimetallic member, responding to the excess current displaces the catch and releases the lever.

22 Claims, 6 Drawing Figures i e/g? a 1 I 9 I! 10 PATENTEDSEP12|912 I 3.691.489

sum 1 OF 2 3 I r1 I) I) I I 5b 4 F g I [5 v I91? W17/ :15? H 1/70 i l 7a Q ,2 I 50 {H 9 i/ 10 Fig 2 I9 2 e! W I X /3 E L ELECTRICAL DISTRIBUTING APPARATUS PROTECTIVE DEVICES THEREFOR BACKGROUND OF THE INVENTION This invention relates to distributing apparatuses for wiring and protective devices therefor, and particularly to distributing apparatuses and automatic circuit breakers therefor.

Generally in each automatic circuit breaker or other disconnect device, a release magnet, backed up by a bimetallic release, disengages a movable contact member from a stationary contact in response to excessive currents. An arc quenching chamber extinguishes the are produced by disengagement of the contact member from its stationary contact. In such distributing apparatuses plugs may emerge from the automatic circuit breakers to engage suitable sockets.

One plug-type of circuit breaker of the above mentioned type is described in German Utility Model Pat. No. 1,945,257. Such plug-type switches or circuit breakers have rectangular housings with connection plugs emerging from one long narrow side. The various operating parts of the circuit breaker are arranged in a substantially square interior.

In order to obtain distributing apparatuses with automatic circuit breakers or other disconnect switches of small dimensions, the operating parts are kept as small as possible and arranged as close together as possible. However there are limits, which are imposed particularly by the required short circuit-breaking power. When a short circuit is cut off an arc is formed. Such an arc releases electrically conductive gases. These gases spread inside the circuit breaker so that additional arcs may be ignited within the circuit breaker. This may destroy the circuit breaker. A quenching or arc extinguishing chamber is arranged as far as possible away from other switch members. Alternately partitions or covers are provided inside the circuit breaker. The general increase in consumption of electric power causes the current carrying capacities of electric mains, that is lines and transformers, constantly to be increased. As a result the current surges passing through such lines during short circuits are also generally higher. It is therefore necessary to equip protective switches such as circuit breakers with increased capacity to cut off high power short-circuit currents. Nevertheless it is desirable that the volume of such switches be maintained small. In particular it is desirable that the height or depth of distributing apparatuses upon which such automatic circuit breakers are mounted be kept small.

Advances in technology have made it possible to make the walls of buildings thinner than heretofor. For this reason it is even more necessary to make the overall height or depth of distributing apparatuses such as panels with automatic circuit breakers smaller than before.

An object of this invention is to overcome these difficulties.

Another object of the invention is to improve distributing apparatuses. Still another object of the invention is to improve protective switches such as circuit breakers.

Still another object of the invention is to furnish automatic circuit breakers of the above mentioned type capable of handling high short-circuit switching power within a small height or depth.

Still another object of the invention is to furnish a distributing apparatus which forms an integral unit with such circuit breakers and offers the possibility of manufacturing complete wiring distributing apparatuses.

SUMMARY OF THE INVENTION According to a feature of the invention the automatic circuit breaker comprises movable contact means, stationary contact means, control means responsive to one condition for moving the movable contact means into engagement with the stationary contact means and responsive to another condition for moving the movable contact means out of engagement with the stationary contact means, a U-shaped housing surrounding the movable contact means and the stationary contact means as well as the control means and having two side portions connected by a narrow central portion, a quenching chamber in one of the side portions, the control means being located in the other of the side portions, the stationary contact means being located in the first side portion, the movable contact means extending through the central portion from the other of the side portions.

According to another feature of the invention plug means extend from in the housing out of the housing into the space between the arms.

According to a more specific concept of the invention a U-shaped housing has a quenching or extinguishing chamber arranged in one arm and a release magnet with a catch or retainer in the other arm. In the con necting duct between the two arms are arranged a contact lever and a bimetallic member which acts as a release. Plug connections extend from inside the housing into the free space between the arms.

According to another feature of the invention quenching plates in the quenching chamber are arranged parallel to each other and to the release magnet.

According to another feature of the invention the distance between the center of the quenching chamber and the center of the release magnet is more than 1.5 times the length of the quenching chamber.

According to another feature of the invention the contact lever and the bimetallic member that serves as a release are arranged substantially perpendicularly to the longitudinal axes of the release magnet and the quenching chamber.

These features furnish a desirable separation of the quenching chamber from the other operating parts which may be jeopardized by hot gases. This is particularly important in the case of the release magnet and the parts interlocking with the lever. These features limit the dangerous spread of hot gases during the disconnect operation in response to a short circuit, by providing only one connecting path of small cross section between the quenching chamber and the release magnet. This relatively long connecting path with its small cross section has the effect of cooling the hot gases. Therefore arc-overs between parts of the switch or circuit breaker, especially of the catch mechanism or the magnetic release, are prevented. The short-circuit switching power is thus considerably increased.

According to another feature of the invention a catch or retainer near the release magnet holds the contacting lever closed in engagement with the stationary contact until the release magnet displaces the catch. A bent off part of the catch is arranged between a pin actuated by the armature of the release magnet and the end of the contact lever. When the release magnet is actuated by a short-circuit current, this has the effect of transmitting a rapid force from the release magnet to the end of the lever after the catch has been displaced. This blow on the lever accelerates disengagement of the lever from the stationary contact; that is it accelerates opening of the switch, it helps further to increase the short-circuit switching power, or the magnitude of the currents cut off.

According to another aspect of the invention a distributing apparatus is formed from a plurality of such disconnect switch means or automatic circuit breaker means which are arranged side-by-side with the arms aligned to form a conduction channel in the space outside the housing between the arms. The cross section of the conduction channel corresponds to the cross section of the recesses formed by the U-shapes of the housings. The channel then forms a passage for conductors that terminate in suitable sockets for the plugs projecting from the housings.

According to another feature of the invention the housings forming the conduction channel are mounted rigidly on a junction box carrying terminals which are electrically connected with the sockets. These electrical connections are preferably of the non-detachable type, for example of the type produced by welding, soldering or riveting.

In this manner a simple, small and particularly flat distribution arrangement is made possible. These arrangements may be assembled economically, namely by prewiring in the factory.

According to another feature of the invention the cross sections of the junction box is made equal to the dimension of the housings along the lengths of the arms.

These and other features of the invention are pointed out in the claims, other objects and advantages of the invention will become known from the following detailed description when read in light of the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view of an automatic circuit breaker embodying features of the invention;

FIG. 2 is a cross sectional view of the device in FIG. 1 with the contacts closed;

FIG. 3 is a cross sectional view of the device in FIG. 1 with the contacts open;

FIG. 4 is a partly cut away perspective illustration of a distributing apparatus embodying features of the invention;

FIG. 5 is a sectional view of the apparatus in FIG. 4 taken between two switches or circuit breakers of FIG. 4; and

FIG. 6 is a sectional view of a junction box utilizing the arrangement of FIG. 4 and taken between two housings, and showing the box in a buried or recessed installation.

DESCRIPTION OF PREFERRED EMBODIMENTS FIG. 1 is a side view illustrating an automatic circuit breaker or automatic disconnect switch embodying features of the invention. For purposes of convenience the word switch is used interchangeably with circuit breaker.

In FIG. 1 a U-shaped housing 1 is formed of two sides or arms 2a and 2b connected by a central portion 3. The free space or indentation 4 formed between the arms 2a and 2b contains two plug connections or plugs 5a and 5b. I

As shown in FIGS. 2 and 3, the arm or side 20 forms an arc quenching chamber or are extinguishing chamber 6. Arranged in the chamber 6 are quenching plates or extinguishing plates 7 and a fixed electrical contact 8 which is connected to the plug connection 5a. The length of the chamber 6 is equal to the inside dimension of the housing at the side 2a. The distance between the centers of the arms 2a and 2b exceeds 1.5 times the length of the chamber 6.

Arranged in the other arm 2b in a release magnet 9 having a coil 10, an armature 11, and a pin 12. A control latch, catch orretainer 13 is articulated about an extension in the yoke of the magnet 9 and is biased toward the right by a catch spring or a retainer spring 14, all within the arm 2b. One end of the coil 10 connects to the plug 5a.

Mounted in the central portion 3 is a contact lever 15. The latter is articulated about and movable within the vertical slot 17a of a guide element 17 by means of bearing pins 15a. In one position of the lever 15 its left end projects into an opening 15b of the catch 13. A bimetallic element 16 cantilevered on the right in the central portion 3 extends longitudinally through the central portion 3 toward a bracket 16a projecting to the right from the catch 13.

The contact lever 15 projects into the sides 20 and 2b and, at a contact point near its right end, engages the fixed contact 8. In this electrically closed position the lever 15 projects into the opening 15b of the catch 13 and bears upwardly against the catch. The guide element 17, aside from forming the oblong slot 17a includes a horizontal portion 17b from which the support 170 for the bimetallic element projects upwardly, and which forms the fastening means for the release magnet A reset button or closing button 18 rides vertically with contact lever 15. A disconnect button or opening button 19, when depressed, displaces the retainer 13 to the left against the force of the spring 14. The bracket 16 terminates in a bent portion 21 in the path of the pin 12.

The circuit breaker, designated 22, in FIGS. 1, 2 and 3 operates as follows.

When the circuit breaker is open or disconnected as shown in FIG. 3, the reset button 18 projects upwardly from the housing 1. When the reset button 18 is depressed, the contact lever 15 is moved counterclockwise, about its right end which performs the function of a fulcrum, and against the force of a spring 20. The reset button 18 keeps the lever moving until its left end locks behind the upper edge of the opening 15b in the catch 13. During this time the bearings 15a of the lever 15 may slide downwardly within the slot 17a of the guide element 17.

When the reset button 18 is released, the spring 20 moves the contact lever upwardly and counterclockwise about the point of contact of its left end with the top edge of the opening 15bin the catch 13 which now acts as a fulcrum. This continues until the right end of the contact lever establishes contact with the fixed contact 8. The spring 20 provides the contact pressure.

runs: no

The automatic circuit breaker 22 in FIGS. 1, 2 and 3 is released by the release magnet 9, or the bimetallic element 16, responding to excessive current. It can, of course, also be released by the release button 19. When it is released by the bimetallic element 16 the left end of the latter pushes the bracket 16a upwardly. When it is released by the release magnet 9, the pin 12 pushes the bracket 16a upwardly. The upward movement of the bracket 16a moves the catch 13 to the left or counterclockwise. This releases the left end of the contact lever 15.

The spring now turns the contact lever 15 upwardly at its left end about the fulcrum point which is formed by its engagement with the contact 8. Thus, the lever 15 moves clockwise about the contact 8. After a short movement about the contact 8, the bearing pins 15a of the contact lever 15 within the vertical slot 17a of the guide element 17 strike against the end of this vertical oblong slot 17a. The bearing pins 15a and the upper end of the slot 17a become the fulcrum about which the lever 15 is moved clockwise by the spring 20. This causes the contact point at the right end of the lever 15 to disengage from the contact 8 so as to open the circuit. The contact lever 15 then moves into the position shown in FIG. 3.

The disengagement of the contact point on the contact lever 15 from the contact 8 creates an are which is quenched by the quenching plates 7 in the quenching chamber 6.

i As stated, the breaker responds to excessive current such as that exhibited during a short circuit. During such a short circuit the armature 11 moves upward and displaces the pin 12. This pin strikes against the bracket 16a at the bent portion 21. As stated, this causes the catch 13 to move counterclockwise. After a certain amount of rotation of the catch 13, the contact lever 15 moves out of the opening 15b. The bent portion 21 now strikes against the end of the contact lever 15 and transmits the blow of the armature 11 to the lever 15. This helps to accelerate the contact lever 15 in its upward movement. It breaks up any welding that may have taken place at the contact point.

As can be seen from the drawings, the height or depth of the automatic circuit breaker is equal to the length of the quenching chamber 6 including the housing walls. This advantageous embodiment permits an automatic circuit breaker capable of handling high short-circuit switching currents to retain a shallow depth.

FIG. 4 illustrates a distributing apparatus. Here several automatic switches 22 are arranged side by side. Each of the automatic switches 22 corresponds to that illustrated in FIGS. 1, 2 and 3. The free spaces or indentations 4 between the arms 2a and 2b of the automatic switches 22 form a conduction channel 23 with an insulating base 24. The latter carries plug-in sockets 25. Continuous transverse openings for receiving the lines to the sockets are provided as shown in FIG. 5 and FIG. 6.

In FIG. 4, a base plate 27 which forms part of a junction box is rigidly connected with the base of the conduction channel 23. The junction box contains a cover 28. The junction box also contains terminals 29 for lines passing to the load circuits as well as for lead wires and terminals 30 for connection to neutral conductors.

The sockets 25 can include screw terminals as shown so that it is possible to form a direct connection of the lines to the load circuits. However, connecting lines between the sockets and the terminals 29 can also be preassembled during the manufacture and be connected in other ways, for example, by welding to the terminals 29 and the sockets 25.

FIG. 6 illustrates an apparatus for concealed installation or recessed installation with an additional insulating box 31 and cover 32. Other possibilities for installation in the wall 33 of a house are made obvious by the embodiments of FIGS. 5 or 6.

The advantages of the distributing apparatus illustrated in FIGS. 4, 5 and 6 can be seen from the drawings. For example, the height of the distributing apparatus is either identical to or slightly greater than the depth of the circuit breakers. The difference is the small wall thickness of an additional box and cover. The invention provides an integral unit of switches and wiring distributor. Moreover, it is possible to produce complete distributing apparatus economically by mass production and still permit replacement of automatic cut-offs by means of plug connections.

While embodiments of the invention have been described in detail it will be obvious to those skilled in the art that the invention may be embodied otherwise without departing from its spirit and scope.

What is claimed is:

1. A. circuit breaking apparatus, comprising movable contact means, stationary contact means, control means responsive to one current condition for moving said movable contact means into engagement with said stationary contact means and responsive to another current condition for moving said movable contact means out of engagement with said stationary contact means, housing means surrounding said movable contact means and said stationary contact means as well as said control means; said housing means forming a first chamber, a second chamber, and an elongated passage connecting said first chamber and said second chamber; said passage having a cross sectional area transverse to its length less than the cross sectional area of said chambers transverse to the length of said passage, said first chamber including said stationary contact means and forming a quenching chamber, said control means being located in said second chamber, said movable contact means extending through said passage from said control means to said second contact means. a

2. An apparatus as in claim 1, wherein said housing means has a U-shape with two arm portions and a central portion, said central portion forming said passage and said arm portions forming said chambers, said arm portions forming between them with said central portion an indent space.

3. An apparatus as in claim 2 further comprising plug means projecting from said housing means into said space for carrying current to said control means when said contact means are engaged with each other.

4. An apparatus as in claim 3, wherein said movable contact means includes a contact lever having one end projecting toward said control means and a second end for contacting said stationary contact means.

5. An apparatus as in claim 4, wherein said control means includes a bimetallic element mounted in said passage and extending into said second chamber.

6. An apparatus as in claim 4, wherein said first chamber includes quenching plates extending transverse to the direction of said passage.

7. An apparatus as in claim 4, wherein said control means includes a release magnet connected to one of said plugs and having a magnetic axis transverse to said passage.

8. An apparatus as in claim 7, wherein said first chamber includes quenching plates extending transverse to the direction of said passage.

9. An apparatus as in claim 8, wherein the distance between the axis of said release magnet and the center of said quenching chamber is more than l.5 times the length of said quenching chamber transverse to said passage.

10. An apparatus as in claim 3, wherein the distance between the center of said second chamber and the center of said first chamber is more than 1.5 times the length of said first chamber transverse to said passage.

11. An apparatus as in claim 7, further comprising spring means for holding the end of said lever out of contact with said stationary contact means, and wherein said control means include catch means for holding said lever so that it contacts said stationary contact means against the force of said spring means, said release magnet releasing said lever from said catch means in response to currents through said release magnet.

12. An apparatus as in claim 1 1, wherein said release magnet includes armature means for moving said catch means to release said lever.

13. An apparatus as in claim 12, wherein said catch means includes a flat portion in the path of said armature means to be moved by said armature means and cause said catch means to release said lever, said flat portion being arranged so as to strike said lever as said catch means moves to release said lever and add momentum to said lever so as to break contact of said lever from said stationary contact means.

14. An apparatus as in claim 2, wherein said housing means includes walls and the depth of said housing means transverse to said passage is equal to the height of said quenching chamber transverse to said passage including the walls at said quenching chamber.

15. An apparatus as in claim 13, wherein said housing includes walls and the depth of said housing transverse to said passage is equal to the height of said quenching chamber transverse to said housing including the walls at said quenching chamber.

16. A distributing apparatus comprising flat panel means, a plurality of circuit breakers; each of said circuit breakers comprising movable contact means, stationary contact means, control means responsive to one condition for moving said movable contact means into engagement with said stationary contact means and responsive to another condition for moving said movable contact means out of engagement with said stationary contact means, housing means surrounding said movable contact means and stationary contact means as well as said control means, said housing means forming a pair of chambers and an elongated passage connecting said chambers to each other, said passage having a cross sectional area transverse to its length less than the area of said chambers to their lengths, the first chamber including said stationary contact means and fprmin a penchin cha her said control means being loc ated in said s econri chainber,

said movable contact means extending through said passage from said control means to said contact means, plug means extending from said housing; and a plurality of sockets for receiving said plug means extending from said housing, and wiring means connecting said plug means, each of said housing means forming an indentation into which said plug means extend, said housing means being arranged so that siad indentations are aligned to form a channel, said panel means covering said channel, said wiring means passing through said channel, said socket means being arranged in said channel.

17. An apparatus as in claim 16, wherein each of said housing means has a U-shape with two arm portions and a central portion, said central portion forming said passage and said arm portions forming said chambers, said arm portions forming between them and said central portion the indentation of each of said housing means.

18. An apparatus as in claim 16, wherein said contact means in each of said housing means includes a contact lever having one end projecting toward said control means and a second end for contacting said stationary contact means.

19. An apparatus as in claim 16, wherein said housing means includes walls and the depth of each of said housing means transverse to said passage is equal to the height of said quenching chambers transverse to said passage including the walls at said quenching chambers.

20. An apparatus as in claim 19, wherein in each of said housing means said control means includes a release magnet connected to one of said plugs and having a magnetic axis transverse to said passage, wherein the distance between the center of'one of said chambers and the center of the other chamber is more than 1.5 times the length of said quenching chamber transverse to said passage, wherein said control means in each of said housing means includes catch means and spring means for holding the end of said lever at said control means so that the other end is out of contact with said stationary contact means, said catch means holding said lever so that it contacts said stationary contact means against the force of said spring means, said release magnet releasing said catch means from said control means in response to current therethrough, said magnetic release means including armature means for moving said catch means to release said lever, said catch means including a flat portion in the path of said armature means and said lever and arranged in the path of movement of said armature means so as to strike said lever as said catch means releases said lever and thereby break the contact of said lever from said stationary contact means.

21. An apparatus as in claim 16 further comprising a junction box, connection means in said junction box for connecting said wiring with a source of power.

22. An apparatus as in claim 21, wherein the depth of the dimension of said junction box is equal to the depth of said housings transverse to said passage. 

1. A circuit breaking apparatus, comprising movable contact means, stationary contact means, control means responsive to one current condition for moving said movable contact means into engagement with said stationary contact means and responsive to another current condition for moving said movable contact means out of engagement with said stationary contact means, housing means surrOunding said movable contact means and said stationary contact means as well as said control means; said housing means forming a first chamber, a second chamber, and an elongated passage connecting said first chamber and said second chamber; said passage having a cross sectional area transverse to its length less than the cross sectional area of said chambers transverse to the length of said passage, said first chamber including said stationary contact means and forming a quenching chamber, said control means being located in said second chamber, said movable contact means extending through said passage from said control means to said second contact means.
 2. An apparatus as in claim 1, wherein said housing means has a U-shape with two arm portions and a central portion, said central portion forming said passage and said arm portions forming said chambers, said arm portions forming between them with said central portion an indent space.
 3. An apparatus as in claim 2 further comprising plug means projecting from said housing means into said space for carrying current to said control means when said contact means are engaged with each other.
 4. An apparatus as in claim 3, wherein said movable contact means includes a contact lever having one end projecting toward said control means and a second end for contacting said stationary contact means.
 5. An apparatus as in claim 4, wherein said control means includes a bimetallic element mounted in said passage and extending into said second chamber.
 6. An apparatus as in claim 4, wherein said first chamber includes quenching plates extending transverse to the direction of said passage.
 7. An apparatus as in claim 4, wherein said control means includes a release magnet connected to one of said plugs and having a magnetic axis transverse to said passage.
 8. An apparatus as in claim 7, wherein said first chamber includes quenching plates extending transverse to the direction of said passage.
 9. An apparatus as in claim 8, wherein the distance between the axis of said release magnet and the center of said quenching chamber is more than 1.5 times the length of said quenching chamber transverse to said passage.
 10. An apparatus as in claim 3, wherein the distance between the center of said second chamber and the center of said first chamber is more than 1.5 times the length of said first chamber transverse to said passage.
 11. An apparatus as in claim 7, further comprising spring means for holding the end of said lever out of contact with said stationary contact means, and wherein said control means include catch means for holding said lever so that it contacts said stationary contact means against the force of said spring means, said release magnet releasing said lever from said catch means in response to currents through said release magnet.
 12. An apparatus as in claim 11, wherein said release magnet includes armature means for moving said catch means to release said lever.
 13. An apparatus as in claim 12, wherein said catch means includes a flat portion in the path of said armature means to be moved by said armature means and cause said catch means to release said lever, said flat portion being arranged so as to strike said lever as said catch means moves to release said lever and add momentum to said lever so as to break contact of said lever from said stationary contact means.
 14. An apparatus as in claim 2, wherein said housing means includes walls and the depth of said housing means transverse to said passage is equal to the height of said quenching chamber transverse to said passage including the walls at said quenching chamber.
 15. An apparatus as in claim 13, wherein said housing includes walls and the depth of said housing transverse to said passage is equal to the height of said quenching chamber transverse to said housing including the walls at said quenching chamber.
 16. A distributing apparatus comprising flat panel means, a plurality of circuit breakers; each of saId circuit breakers comprising movable contact means, stationary contact means, control means responsive to one condition for moving said movable contact means into engagement with said stationary contact means and responsive to another condition for moving said movable contact means out of engagement with said stationary contact means, housing means surrounding said movable contact means and stationary contact means as well as said control means, said housing means forming a pair of chambers and an elongated passage connecting said chambers to each other, said passage having a cross sectional area transverse to its length less than the area of said chambers to their lengths, the first chamber including said stationary contact means and forming a quenching chamber, said control means being located in said second chamber, said movable contact means extending through said passage from said control means to said contact means, plug means extending from said housing; and a plurality of sockets for receiving said plug means extending from said housing, and wiring means connecting said plug means, each of said housing means forming an indentation into which said plug means extend, said housing means being arranged so that siad indentations are aligned to form a channel, said panel means covering said channel, said wiring means passing through said channel, said socket means being arranged in said channel.
 17. An apparatus as in claim 16, wherein each of said housing means has a U-shape with two arm portions and a central portion, said central portion forming said passage and said arm portions forming said chambers, said arm portions forming between them and said central portion the indentation of each of said housing means.
 18. An apparatus as in claim 16, wherein said contact means in each of said housing means includes a contact lever having one end projecting toward said control means and a second end for contacting said stationary contact means.
 19. An apparatus as in claim 16, wherein said housing means includes walls and the depth of each of said housing means transverse to said passage is equal to the height of said quenching chambers transverse to said passage including the walls at said quenching chambers.
 20. An apparatus as in claim 19, wherein in each of said housing means said control means includes a release magnet connected to one of said plugs and having a magnetic axis transverse to said passage, wherein the distance between the center of one of said chambers and the center of the other chamber is more than 1.5 times the length of said quenching chamber transverse to said passage, wherein said control means in each of said housing means includes catch means and spring means for holding the end of said lever at said control means so that the other end is out of contact with said stationary contact means, said catch means holding said lever so that it contacts said stationary contact means against the force of said spring means, said release magnet releasing said catch means from said control means in response to current therethrough, said magnetic release means including armature means for moving said catch means to release said lever, said catch means including a flat portion in the path of said armature means and said lever and arranged in the path of movement of said armature means so as to strike said lever as said catch means releases said lever and thereby break the contact of said lever from said stationary contact means.
 21. An apparatus as in claim 16 further comprising a junction box, connection means in said junction box for connecting said wiring with a source of power.
 22. An apparatus as in claim 21, wherein the depth of the dimension of said junction box is equal to the depth of said housings transverse to said passage. 